Effect of melt treatment on the microstructure and magnetic properties of Nd2Fe14B/α-Fe nanocomposites

Melt-spun Nd9.5Fe81Zr3B6.5 ribbons were prepared under different quenching temperature. The effect of melt treatment on the microstructure and magnetic properties of Nd2Fe14B/α-Fe nanocomposites was studied by X-ray diffraction, scanning electron microscopy (SEM), differential scanning calorimeter, transmission electron microscopy observations, and magnetization measurements. It was found that melt spinning at different quenching temperature caused the as-quenched ribbons to have distinctive structure. Depending on the quenching temperature, nanocrystalline structure, partially amorphous structure containing nanophases or entirely amorphous structure could be obtained. Moreover, with increasing initial quenching temperature, the microstructure of optimally heat treated ribbons becomes coarser and more irregular, and the magnetic properties of them deteriorated. It is believed that the alteration of melt characteristics which are highly sensitive to the melt temperature may be the cause for the change of glass forming ability, the microstructure and magnetic properties of the ribbons.